Identification and characterization of an ene-reductase from Corynebacterium casei

The asymmetric reduction of α , β -unsaturated compounds conjugated with electron-withdrawing group by ene-reductases (ERs) is a valuable method for the synthesis of enantiopure chiral compounds. This study introduced an ER from Corynebacterium casei ( Cc ER) which was heterologously expressed in Escherichia coli BL21(DE3), and the purified recombinant Cc ER was characterized for its biocatalytic properties. Cc ER exhibited the highest specific activity at 40 °C and pH 6.5, and showcased appreciable stability below 40 °C over a pH range of 6.0–7.0. The enzyme displayed high resistance to methanol. Cc ER accepted NADH or NADPH as a cofactor and exhibited a broad substrate spectrum towards α , β -unsaturated compounds. It achieved complete conversion of 2-cyclohexen-1-one and good performance for stereoselective reduction of ( R )-carvone (conversion 98 %, diastereoselectivity 96 %). This study highlights the robustness and potential of Cc ER.